1. Field of the Invention
The present invention relates to a conveying device for a rod, in particular, to a conveying device configured to sequentially pick up a plurality of randomly piled rods by using a robot and conveying the picked up rods to a predetermined place.
2. Description of the Related Art
In sequentially picking up and conveying a plurality of rods, which are randomly piled on a pallet or a conveyor, by using a robot, conveying efficiency and cost of the operation are varied depending on where the robot grips or sucks the rod. For example, Japanese Unexamined Patent Publication (Kokai) No. 4-93191 discloses a configuration wherein a rod-shaped workpiece 22 in a box is electromagnetically attracted and picked up by using a robot hand 62 attached to a robot wrist element via a floating mechanism 91.
Further, Japanese Unexamined Patent Publication (Kokai) No. 4-348887 discloses a configuration wherein a rod “A” is gripped by a gripper 4 provided on a front end of a robot arm 1, and inserted into a spool hole “C” while being spirally moved.
In the method of Japanese Unexamined Patent Publication (Kokai) No. 4-93191 wherein the lateral side of the rod is attracted, it is necessary to use a mechanism for gripping one end of the rod and regrip the rod by using the mechanism, in order to convey the rod in a vertical state. Further, it is necessary to use a floating mechanism for avoiding a mistake when gripping due to a small positional error between the rod and the robot hand. Such a floating mechanism is not cost efficient.
On the other hand, in the method of Japanese Unexamined Patent Publication (Kokai) No. 4-348887 wherein one end of the rod is gripped by means of a chuck or the like, it is necessary that each supplied rod is previously positioned in a vertical state. Therefore, the applicable range of this method is limited. Further, in the method, it is difficult to pick up the rods one-by-one among a plurality of randomly piled (or closely-spaced) rods.